Improvement in piano-fortes



UNITED STATES PATENT OFFICE.

WILLIAM BOURNE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO NATHANIEL GUMMINGS, OF SAME PLACE.

IMPROVEM ENT IN PIANO-FORTES.

Specification forming part of Letters Patent No. @7,717, dated February 17, 1F63.

To .'LZZ whom it Wtay aon/cern,.-

Beit known that l, WILLIAM BOURNE, a citizen of the United States of America, and a resident of Boston, in the county of Suffolk and State of Massachusetts, have invented a new and useful Improvement in Piano-Fortes; and do hereby declare the sa-me to be fully described in the following specification, and represented in the accompanying drawings, of which` Figure l is a top view of the iron frame, the sounding-board, and the case ofthe instrument in their relativepositions. Fig. 2 is atop view of the case and the sounding-board as they appear without the iron frame. Fig. 3 is a longitudinal section, and Fig. 4 a transverse section, of the case, the sounding-board, and the iron frame.

The principle or nature of my invention is found in an improved arrangement, which consists in extending the sounding-board in rear of the ham mer-passage thereof and underneath the straining-pin bar of the iron frame, and from side to side and end to end of the case, and so suspending the said bar over the part of such board which is in rear of the hammer passage that there may be a free and uninterrupted vibration-space between the two, substantially as hereinafter described.

In the construction of ordinary piano fortes it has been customary to extend along underneath and close aga-inst the straining-pin bar or plate of the iron frame a strong wooden backing or blocking, such iillin g a considerable aportion of the case, and serving not only to strengthen it, but give support to the iron frame. This backing or blocking has been considered necessary to the construction of the instrument, the sounding-board being ar ranged in front of it, or between it and the front board of the case.

In carrying out my invention I entirely dispense with the said blocking, and within the space usually occupied thereby and in rear of the hammer-passage I arrange an extension of the sounding-board, or what perhaps may be more properly termedan auxiliary soundingl board,7 and between the upper surface of the i s aid extension or auxiliary sounding-board and the lower surface of the straining-pin bar or plate I leave a space sufiicient to admit of the free, uninterrupted vibration of the said auxiliary sounding-board or extension.

In the drawings, A is the case of the instrnm ent B, the metallic or iron string-frame (l, the soundingboard 5 a, the hammerpassage, which in this case consists of a slot made through the sounding-board. It is through this passage that the hammers ascend or pass in order to strike the strings. The soundingboard, near its edges, rests on a shelf or ledge, b. This shelf or ledge is arranged so as to project from the inner surfaces of the rear side and the two ends of the case. Furthermore, there is upon the upper surface of the soundingboard, and close to its edge or edges, an abutment, ledge, or prejection, c, the same being formed and arranged as shown in Figs. 2, 3, and 4. It is on the upper surface of this abutment or ledge c that the iron frame B rests or is supported. In consequence of this ledge c there will be formed between the strainingpin bar b (of the iron frame) and the part e (or the auxiliary sounding-board extended in rear of the hammer-passage a) a vibration-space, lf, which may have a depth of about one-half an inch. By means of the ledge c the strainingpin bar b becomes suspended or bridged over the extended part c or auxiliary soundingboard.

From the above it will be seen that by my improvement there is a material gain in the amount of sounding-board; also, that the usual heavy blocking' used in rear of the sounding-board is dispensed with. In consequence of this latter, the whole case of the instrument is enabled to cooperate to better advantage with the sounding-board, or enables the latter to operate with a better musical effect than when the said backing or blocking is used.

Itis found that my improvement is productive not only of a greater extent of vibration of the sonndingboard and case, but a colisequent increase in the volume of tone. The

and so suspending the said bar over the part of such board which is in rear of the hammerpassage that there may be a free or uninterrupted vibration-space, f, between the two, substantially as hereinbefore described.

WILLIAM BOURNE. Witnesses R. H. EDDY, F. P. HALE, Jr. 

